In many areas of the country, the moisture content of the crawl space under buildings that do not have basements have created quite a problem. The moisture retained in the crawl space causes the floor joist to eventually rot. Many buildings have their floors insulated in which event the moisture in the crawl space waterlogs the insulation. Also, the moisture causes mold and mildew growth and related odors. Moisture also increases the insect population. All of these are only some of the problems created by moisture in the crawl space and, as a result, attempts have been made to eliminate such moisture by ventilating the crawl space, but to my knowledge none of these attempts have ever been completely satisfactory. The present invention seeks to solve these moisture related problems.